Which chemical is used to test the presence of starch in a food sample?

Carbohydrates are present in our food in the form of starch as well as sugars.

We can perform a simple test to check if our food contains starch.
This can be done by putting 2-3 drops of dilute iodine solution on the food sample.
If a blue-black colour appears on the tested food sample, we can infer the presence of starch in the food sample.